# Fruity [github](https://github.com/nvzqz/fruity) [crates.io](https://crates.io/crates/fruity) [docs.rs](https://docs.rs/fruity) Rusty bindings for Apple libraries, brought to you by [@NikolaiVazquez](https://twitter.com/NikolaiVazquez). ## Index 1. [Donate](#donate) 2. [Usage](#usage) 1. [Feature Flags](#feature-flags) 3. [Goals](#goals) 1. [Idiomatic Rust](#idiomatic-rust) 2. [Zero Cost](#zero-cost) 4. [License](#license) ## Donate If this project is useful to you, consider [sponsoring me](https://github.com/sponsors/nvzqz) or [donating directly](https://www.paypal.me/nvzqz)! Doing so enables me to create high-quality open source software like this. ❤️ ## Usage This library is available [on crates.io][crate] and can be used in your project by adding the following to your project's [`Cargo.toml`]: ```toml [dependencies.fruity] version = "0.3.0" ``` ### Feature Flags Each module for a library or framework has its own [feature flag](https://doc.rust-lang.org/cargo/reference/features.html) with the same name. For example, this is how you enable the [`foundation`](https://docs.rs/fruity/0.3.0/fruity/foundation/index.html) module: ```toml [dependencies.fruity] version = "0.3.0" features = ["foundation"] ``` This feature transitively enables the [`objc`](https://docs.rs/fruity/0.3.0/fruity/objc/index.html) feature/module. ## Goals ### Idiomatic Rust Fruity makes interfacing with these C and Objective-C APIs feel natural in Rust. - **Automatic Reference Counting.** Fruity takes advantage of Rust's [ownership model](https://doc.rust-lang.org/book/ch04-01-what-is-ownership.html) to handle object reference counting for you. [`NSObject`](https://docs.rs/fruity/0.3.0/fruity/objc/struct.NSObject.html) is a smart pointer that calls [`retain`](https://developer.apple.com/documentation/objectivec/1418956-nsobject/1571946-retain) on [`Clone`](https://doc.rust-lang.org/std/clone/trait.Clone.html) and [`release`](https://developer.apple.com/documentation/objectivec/1418956-nsobject/1571957-release) on [`Drop`](https://doc.rust-lang.org/std/ops/trait.Drop.html). This is exactly how Rust's [`Arc`](https://doc.rust-lang.org/std/sync/struct.Arc.html) works. - **`Option`.** In Objective-C, all objects are nullable unless marked with `_Nonnull`. This often leads to either very defensive checks or careless ignoring of null objects. Fruity reverses that and instead makes all objects (such as [`NSObject`](https://docs.rs/fruity/0.3.0/fruity/objc/struct.NSObject.html)) non-null by default. An object can be made nullable by wrapping it with [`Option`](https://doc.rust-lang.org/std/option/enum.Option.html). To make FFI safe and easy, the following Objective-C and Rust types are ABI-compatible: - `NSObject * _Nonnull` and `NSObject` - `NSObject * _Nullable` and `Option` This is because [`NSObject`](https://docs.rs/fruity/0.3.0/fruity/objc/struct.NSObject.html) is a [`#[repr(transparent)]`](https://doc.rust-lang.org/nomicon/other-reprs.html#reprtransparent) wrapper around a [`NonNull`](https://doc.rust-lang.org/std/ptr/struct.NonNull.html) pointer. - **`Result`.** In Objective-C, methods take a pointer to where an [`NSError`](https://developer.apple.com/documentation/foundation/nserror) is placed upon failure. This makes it easy to avoid error handling and assume the happy path, which can lead to bugs when errors occur. Fruity instead returns a [`Result`](https://doc.rust-lang.org/std/result/enum.Result.html), which is the canonical way to handle errors in Rust. This ensures that errors must be acknowledged in some way. - **Natural inheritance.** Most of these types are classes that inherit from each other. Because true inheritance is not possible in Rust, Fruity uses [`Deref`](https://doc.rust-lang.org/std/ops/trait.Deref.html) to model Objective-C subclassing. - **Builder Pattern.** Types like [`DispatchQueue`](https://docs.rs/fruity/0.3.0/fruity/dispatch/struct.DispatchQueue.html) have many configurable inputs to create an instance. Many of these inputs have standard default values, so it is cumbersome to specify them all each time. Swift solves this by having default parameters in [`init`](https://developer.apple.com/documentation/dispatch/dispatchqueue/2300059-init). However, Rust does not have default function parameters. Fruity instead solves this using the [builder pattern](https://doc.rust-lang.org/1.0.0/style/ownership/builders.html). See [`DispatchQueueBuilder`](https://docs.rs/fruity/0.3.0/fruity/dispatch/struct.DispatchQueueBuilder.html) as an example. This reduces and simplifies code for creating dispatch queues. ### Zero Cost Using Fruity to interface with Objective-C libraries should have as little runtime cost as writing the same code directly in Objective-C. This is true for the following: - **Calling object methods.** Method dispatch is always direct and does not need the error checking overhead of other wrappers that use the [`objc::msg_send!`](https://docs.rs/objc/0.2.*/objc/macro.msg_send.html) macro. This also reduces the size of your program by not emitting panics that would otherwise never get called. This library is carefully written to ensure that calls to [`objc_msgSend`](https://developer.apple.com/documentation/objectivec/1456712-objc_msgsend) are always done with the correct object type, method selector, and arguments. - **Getting a static class.** Getters like `NSString::class` retrieve the class directly through its symbol. This is instantaneous, especially when compared to calling into the Objective-C runtime via [`objc_getClass`](https://developer.apple.com/documentation/objectivec/1418952-objc_getclass). - **Creating an `NSString` from a Rust string literal.** The [`nsstring!`](https://docs.rs/fruity/0.3.0/fruity/macro.nsstring.html) macro creates an `NSString` literal (i.e. `@"string"`) at compile time. There is no runtime dispatch/allocation/initialization cost. Some parts of this library still aren't zero cost. Your help would be much appreciated here! These are: - **The `selector!` macro.** See [issue #2](https://github.com/nvzqz/fruity/issues/2) for details. ## License This project is released under either the [MIT License](https://github.com/nvzqz/fruity/blob/main/LICENSE-MIT) or [Apache License (Version 2.0)](https://github.com/nvzqz/fruity/blob/main/LICENSE-APACHE), at your choosing. [crate]: https://crates.io/crates/fruity [`Cargo.toml`]: https://doc.rust-lang.org/cargo/reference/manifest.html